Spot welding machine



July 6, 1937. c. A. FRICK 2,085,967

SPOT WELDING MACHINE 7 Filed Sept. 30, 1935 1 13. 2 J5 14 111/? 16 J1 J5,

A TTORNEYS 25 6 interposed between the headand the base.

Patented July 6, 1937 UNITED STATES PATENT OFFICE '7 Claims.

My invention relates to improvements in welding machines and particularly tomachines of that type known as the electric spot welder.

One of the objects of my invention is to provide an extremely efficient welder which, at the same time, may be manufactured at a minimum cost. I For the purpose of disclosing my invention I have illustrated an embodiment thereof in the accompanying drawing in which:

Fig. 1 is a perspective view of a welder embodying my invention;

Fig. 2 is a side elevation partly in section of a welder embodying my invention; Fig. 3 is an end view thereof; and

Fig. 4 is a diagrammatic view of the circuit arrangement.

In the embodiment of the invention illustrated, I provide a hollow base I in which are adapted to be mounted the transformer windings 2. Secured to this base is a head 3 having flattened flanges 4 by which it is secured by the bolts 5 to the base I. This head is suitably insulated from the base by means of a plate of insulating material In addition to the base I I also provide a front plate I which is slightly spaced from the base I and which is likewise secured to the flange 4'by the bolts 5, the insulating plates 6 also being inter posed between the head 3 and the front plate.

The head 3 is provided with an overhanging arm' 8 from which is supported the upper electrode carrier. This carrier, in general shape, is L- shaped, the long leg of the L being arranged horizontally, and the short leg I8 projecting vertically and overlapping the end of the arm 8. The electrode carrier is movably supported on the arm 8 by two pairs of links which carry the same permitting a vertical movement of the electrode. To this end, one of the links I I of a pair is pivoted at I2 to the arm 8 and at its opposite end at point I3 to the leg 9 of the electrode carrier. The opposite link I4 crosses thelink I I and is connected at the point 3J5 to the arm 8 and at the point I6 to the leg 9 of the electrode carrier. The two pairs of links, disposed on opposite sides of the arm 8, thus form a parallel linkageconnection between the arm 8 and the electrode carrier. The

carrier is provided on its side faces with vertical- 1y extending heat-radiating fins III" on the leg I0 and horizontally extending radiating fins 8 on the arm 9, and the. electrode I8 preferably extends through an opening passing through the leg I8 and is held in position by a set screw extending through the leg and engaging the electrode. A

pair of clamp bars I3 and 28 embrace the electrode. The clamp bar I9 is connected to one terminal of the secondary of the transformer by a conductor 22 and the clamp bar 20 is connected to the-bar I9 by means of suitable screws 2 I. 5

The opposite electrode support comprises an arm 23 projecting forward from the front plate I and recessed to receive the electrode arm 26 having at its end a vertically extending electrode 2'! adapted to cooperate with the movable electrode I8. This arm 23 is ribbed as at 28 for heat dissipation. The opposite terminal of the secondary winding is connected to a conductor 29, which in turn has a portion 30 projected forwardly and connected to a clamp 23 partially surrounding the 15 electrode arm 26 and held thereon by a second clamp 24.

An operating arm 3I, preferably taking the form of a pair of arms straddling the head 3, is connected at its forward end tothe leg 9 of the upper electrode carrier. These arms, in practice, form a continuation of the arms I4. This arm provides a means for moving the electrode carrier vertically and is operated by an operating rod 32 which projects through a cross arm 33 between the two legs of the arm 3| and is provided at its upper end with a coil spring 34 interposed between a collar 35' and a stop nut 35 on the upper end of the rod. Beneath the cross arm 33 I provide on the rod 32 an adjustable stop or collar 36 a which, as the rod 32 is moved downwardly, will engage a flexible switch plate 31 depressing the same and causing the contacts 38, mounted on a conducting plate 38 and insulated from the plate 31, to engage with the contacts '39 closing the circuit through the primary winding of the transformer. In operation, the spring 34 is suiiiciently strong to move the upper electrode carrier downwardly and into firm contact with the parts to be welded, inserted between the upper and lower electrodes, before the collar 36 engages the switch arm 31 to close the circuit through the transformer. Likewise, when the pressure is released from the rod 32, this rod may move upwardly sufficiently to permit the switch of the 45 transformer to open without releasing the electrodes. This permits the weld to cool before the pressure is released. To insure perfect insulation, the switch arm 31 is provided with an insulating plate 40 on its upper side at the point where the collar'36 engages the same.

The welder is preferably mounted upon a suitable stand as 4 1 which is provided with an arm 42 pivotally connected at one end to the rod 32 and at its opposite end to a stationary arm 43. 55

This arm in turn is connected by a rod 44 with a foot treadle d pivoted at 46 to a downwardly extending arm 41. A return spring 48 is connected to the arm 42 so that when the pressure is re- 5 lieved from the foot treadle 45 the rod 32 will be raised and with it the electrode 48. r

In Fig. 4 I have illustrated diagrammatically the circuit arrangement of the electrodes, to show primarily the means for adjusting the heat 19 of the welder. In this figure it will be noted that I provide a fuse block 49 with a fuse socket 50 arranged in the circuit in such a manner that when a fuse is inserted in this socket a circuit will be closed through the entire primary of the transformer. If, however, the fuse plug is re moved from the socket 50 and inserted in the fuse socket 51, the current will pass through only a portion of the primary winding, thus materially reducing the heat of the welder. As shown 29 in Fig. 2, this fuse block 49 is exposed through the side opening 52 of the base i and a slide plate 53 covers that socket in which a fuse plug is not inserted, the arrangement being such that the head of the plug will be in the path of the slide 53, so that, in order to insert a plug in one socket, the fuse plug must be removed from the other socket so that the slide may be slid to the proper position.

I claim as my invention:

1. In a spot welding machine, the combination with a hollow base having an open front, of a transformer mounted in said base, a front plate for said base arranged in front of said transformer, a lower electrode carrier projecting from said front plate, a head mounted on the top of said base and plate and an overhanging arm carried by said head, an upper electrode carrier movably mounted on said arm having a portion extending parallel with said arm, and operating means connecting said arm and portion imparting a vertical right line movement to said portion relatively to said arm.

2. In a spot welding machine, the combination with a hollow base, of a transformer mounted in said base, a cover for said transformer, a lower electrode carrier projecting from said cover, a head connecting said base and cover, an overhanging on said base, an upper electrode carrier comprising an L-shaped member, one leg of said L extending parallel with said overhanging arm, the other leg of said carrier extending vertically and having means for receiving an upper electrode, and operating means connecting said arm and parallel leg and imparting a vertical right line movement to said parallel leg relatively to said arm.

3-. In a spot welding machine, the combination with a stationary bottom electrode, of an upper electrode surrounded by a large mass of heat conducting material movable therewith, a head and means for pivotally connecting said upper electrode to said head and insuring a vertical right line movement of said electrode.

4. In a spot welding machine, the combination with a base, of a lower electrode mounted on said base, an overhanging arm mounted on said base, an electrode carrier comprising a large mass of heat dissipating material, an electrode mounted in said carrier and a lazy-tong connection between said carrier and said head for moving said carrier in a right line direction.

5. In a spot welding machine, the combination with a base, of a stationary electrode supported on said base, a head carried on said base and an L-shaped electrode carrier, an upper electrode extending through one leg of said carrier and a lazy-tong connection between the other leg of said carrier and said head for insuring a right line movement between said carrier and said head.

6. In a spot welding machine, the combination with a stationarily mounted electrode carrier, of an arm overhanging said carrier, a movable electrode carrier having a portion extending substantially parallel with said overhanging arm, and a lazy-tong connectionbetween said overhanging arm and said parallel portion for imparting a. vertical right-line movement to said parallel portion.

'7. In a spot welding machine, the combination with a stationary electrode carrier, an arm overhanging said electrode carrier and extending substantially parallel therewith, a movable electrode carrier supported by said arm and comprising an L-shaped member, one leg of which extends substantially parallel with said arm and the other leg of which is adapted to receive an electrode and a lazy-tong connection between said parallel leg and the overhanging arm for imparting a substantially vertical right-line movement to said movable electrode carrier.

CHESTER A. FRICK. 

